we could help with this alternative for our customers who did want to order parts of
LTC3565IDD#PBF, but the lead-time is approximately 52 weeks:
LTC3411AEDD#PBF / LTC3411AEDD#PBF-ND as IC REG BUCK ADJ 1.25A 10DFN capable up to 2,5 MHz as maximal frequency vs the requested 4 MHz from ADI as well.
Please review the datasheets to ensure the alternative will work for your application.